net-timestamp: fix allocation error in test

A buffer is incorrectly zeroed to the length of the pointer. If
cfg_payload_len < sizeof(void *) this can overwrites unrelated memory.
The buffer contents are never read, so no need to zero.

Fixes: 8fe2f761cae9 ("net-timestamp: expand documentation")

Reported-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/timestamping/txtimestamp.c

@@ -192,7 +192,6 @@ static int recv_errmsg(int fd)
 	memset(&msg, 0, sizeof(msg));
 	memset(&entry, 0, sizeof(entry));
 	memset(ctrl, 0, sizeof(ctrl));
-	memset(data, 0, sizeof(data));
 
 	entry.iov_base = data;
 	entry.iov_len = cfg_payload_len;